Hmm, 100 jobs versus the air quality for over 9,000,000 other people (and maybe more – I’m just counting the Chicagoland area). How is that even a debate? And land-use? Again, not really a debate except by debating societies…

While many environmentalists are cheering the closing, it raises new environmental and land-use challenges. It will also be an economic blow to Hammond, and to about 100 employees…Similar situations are playing out nationwide as aging coal plants close, including a Dominion plant in Salem, Mass.; six Midwestern and Eastern coal plants owned by FirstEnergy Corp.; and, potentially, the Fisk and Crawford plants in Chicago in coming years.

Lower natural gas prices from the increase in hydraulic fracturing, or fracking, of shale gas deposits have made it much less profitable to produce electricity from coal. This is especially true for facilities like State Line and the Chicago coal plants, which sell electricity on a highly competitive short-term wholesale market rather than through long-term contracts.

“These companies bought coal plants based on certain assumptions about the price of natural gas,” said William Boyd, a professor of energy law at the University of Colorado. “Shale gas turned their world upside down, and retrofitting old coal plants to meet new environmental regulations doesn’t make sense anymore.”

Some coal plants elsewhere in the country have been retrofitted to burn natural gas. But Dominion and Midwest Generation, which owns the Chicago plants, said converting would be too expensive.

Doug McFarlan, a spokesman for Midwest Generation, said, “We will continue to evaluate numerous factors — including the capital expenditures required to comply with environmental regulations and market conditions that impact our ability to recover costs — in making decisions about future investments in any of our power generating units.”

Dominion had planned to close State Line in 2014, but last summer the company said the plant would be shut down by March.

Environmental advocates have long said the sooner the better, since medical studies link emissions from coal plants to higher rates of asthma attacks, cardiac disease and premature death among surrounding residents.